This invention relates to a cooling and heating device which is provided by adding a heating cycle circuit including a refrigerant heater to a cooling cycle circuit.
In most conventional cooling and heating devices, a refrigerant heater, which is a heat supply source in the heating operation, is incorporated in a cooling cycle circuit including a compressor, an outdoor heat exchanger (or a cooling condenser), a capillary tube and an indoor heat exchanger (or a cooling evaporator). In general, the refrigerant heater is provided between the indoor heat exchanger and the compressor, and in the cooling operation, low temperature refrigerant gas flows in the refrigerant heater. The flow of refrigerant through the refrigerant heater is permitted during the cooling operation, because the refrigerant heater is not in operation during the cooling operation and not obstructive with respect to the cooling operation.
However, the conduction of refrigerant to a refrigerant heater which is not in operation frequently results in the occurrence of problems in the refrigerant heater. In other words, dew is formed on the refrigerant heater by the conduction of the refrigerant, which causes corrosion.
In switching the cooling operation over to heating, it is difficult, because of the resistance of the capillary tube, to purge the refrigerant into the heating cycle circuit through the capillary tube. Therefore, it is necessary to provide a purging bypass circuit including an operating element such as an electromagnetic valve. Thus, the cooling and heating device of this type becomes rather intricate in construction.